Removing async API from blobstore-largeblob

Tested with ninefold-storage:
```
C:\...\jclouds-examples\blobstore-largeblob>java -jar \
  target\blobstore-largeblob-jar-with-dependencies.jar ninefold-storage ... \
  ... target\blobstore-largeblob.jar randome23544354 largeblob
Sucessfully uploaded eTag(randome23544354/largeblob) 8049 bytes with 1006 bytes/s (8049 bytes)
```